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Single sign-on
Single sign-on (SSO) is an authentication arrangement where a user authenticates once to an identity provider and then obtains services from multiple applications without presenting credentials again to each one.
Single skating
Single skating: men's and women's singles figure skating, an ISU discipline of solo jumps, spins, and footwork. Two programs (2:50 short, 4:00 free), scored since 2004 under the IJS point system with TES, GOE, and components.
Single source of truth
Single source of truth (SSOT): a data management principle naming one authoritative system per business fact, with all other systems holding copies. Covers implementation patterns, MDM relationship, risks, and data mesh alternatives.
Single spontaneous delivery
Single spontaneous delivery (ICD-11 JB20; ICD-10 O80): birth of one neonate by unassisted, nonoperative vaginal delivery without induction, instruments, or cesarean; subcategories JB20.0 vertex and JB20.1 breech.
Single Supervisory Mechanism
The Single Supervisory Mechanism (SSM) is the system under which the European Central Bank directly supervises the largest euro area banks, operating since November 2014.
Single system image
Single system image (SSI) is a computing paradigm that makes a cluster of machines appear to users and applications as one large, unified computer, hiding the underlying distributed resources.
Single top-quark production
Single top-quark production is the electroweak creation of one top quark rather than a pair, through the Wtb vertex, first observed at Fermilab's Tevatron in 2009.
Single transferable vote
The single transferable vote (STV) is a proportional electoral system in which voters rank candidates in multi-member constituencies and seats fill by quota, used in Ireland, Malta, and Australia.
Single transverse palmar crease
Single transverse palmar crease, also called single palmar crease or formerly simian crease, is a fusion of the two transverse palm creases into one line, seen in about 1 in 30 people, twice as often in males, and associated with Down syndrome and other conditions.
Single umbilical cord artery
Single umbilical artery (SUA, two-vessel cord): a cord with one artery instead of two, seen in about 1% of pregnancies; associated with renal and cardiac anomalies, growth restriction, and increased stillbirth risk, managed with surveillance.
Single UNIX Specification
The Single UNIX Specification, published by The Open Group since 1994, defines the interfaces and utilities an operating system needs for UNIX certification and trademark use.
Single unprovoked seizure
A single unprovoked seizure is a seizure with no structural or metabolic cause, affecting about 150,000 US adults each year and carrying a 43% risk of recurrence by 2 years.
Single Whip Law
The Single Whip Law (一条鞭法) was a Ming dynasty fiscal reform that consolidated a locality's taxes, labor services, and levies into one payment in silver.
Single White Female
Single White Female is a 1992 Barbet Schroeder psychological thriller starring Bridget Fonda and Jennifer Jason Leigh, adapted from John Lutz's novel S.W.F. Seeks Same, about a roommate who assumes another woman's identity; Columbia Pictures released it August 14, 1992.
Single-atom alloy
A single-atom alloy is a bimetallic heterogeneous catalyst in which small amounts of one metal are atomically dispersed in the surface of a different, more inert metal.
Single-atom alloy hydrogenation catalysts
Single-atom alloy hydrogenation catalysts (SAAs) are bimetallic catalysts in which isolated dopant atoms such as palladium sit dilute in a noble host surface, enabling selective hydrogenation.
Single-atom catalyst
A single-atom catalyst is a heterogeneous catalyst in which isolated individual metal atoms are dispersed on a solid support, so every metal atom is exposed and available for catalysis.
Single-atom catalysts for oxygen evolution
Single-atom catalysts for oxygen evolution are electrocatalysts in which isolated metal atoms on a support drive the oxygen evolution reaction, the efficiency bottleneck of water electrolysis.
Single-atom CO2 electroreduction
Single-atom CO2 electroreduction is the electrochemical conversion of CO2 into fuels and chemicals like carbon monoxide and formate, using isolated single metal atoms as catalysts.
Single-atom EELS spectroscopy in STEM
Single-atom EELS spectroscopy in STEM identifies and chemically analyzes individual atoms using electron energy loss spectroscopy in a scanning transmission electron microscope, first demonstrated in 2000.
Single-atom electron spin qubit in silicon
A quantum bit formed from the spin of a single electron bound to an implanted phosphorus atom in silicon, first demonstrated at the University of New South Wales in 2012.
Single-atom magnet
A single-atom magnet is an individual magnetic atom adsorbed on a surface that retains its magnetization without an external field, so its two states can store one bit of information.
Single-atom magnet Ho on MgO
A single-atom magnet Ho on MgO is a holmium atom on magnesium oxide that keeps its magnetization, identified in 2016 as the first stable single-atom magnet.
Single-atom magnetic memory
Single-atom magnetic memory is an experimental storage concept in which a single magnetic atom on a surface holds one bit, demonstrated on holmium atoms at IBM in 2017.
Single-atom nanozymes
Single-atom nanozymes (SAzymes) are artificial enzyme mimics in which isolated metal atoms dispersed on a solid support act as well-defined active sites, combining nanozyme catalysis with single-atom catalyst precision.
Single-atom Pt/CeO2 catalysts
Single-atom Pt/CeO2 catalysts are heterogeneous catalysts in which isolated platinum atoms are dispersed on a ceria support, studied mainly for the water-gas shift reaction, CO oxidation, and automotive catalysis.
Single-atom qubit in silicon
A single-atom qubit in silicon is a quantum bit stored in the spin of a single phosphorus atom, proposed by Bruce Kane in 1998 and first demonstrated in 2012.
Single-atom Ru catalysts on nitrogen-doped carbon for acidic oxygen evolution
Single-atom Ru catalysts on nitrogen-doped carbon anchor isolated ruthenium atoms in four nitrogen sites on carbon, driving acidic oxygen evolution for proton exchange membrane water electrolyzers.
Single-atom sintering and redispersion dynamics
Single-atom sintering and redispersion dynamics describes how isolated metal atoms on catalyst supports aggregate into clusters under reaction conditions, and how treatments like oxidation can redisperse them back to single atoms.
Single-atom skeletal editing
Single-atom skeletal editing is a set of chemical reactions that insert, delete, or swap exactly one atom in a molecule's core skeleton, defined by Sarpong and Levin in 2022.